The fourth annual San Diego Festival of Science & Engineering engaged an estimated 50,000 people in science, technology, engineering and math (STEM) content in 2012. Across several months, the activities ranged from scientist/classroom collaborations to a week-long series of fun, engaging events in multiple venues, culminating in the grand finale EXPO DAY at PETcO Park. This sponsor and program evaluation acknowledges stakeholders, shares data collected from audience surveys, and evaluation findings.